1) Conventional techniques for the formation of AgI grain and properties of AgI are described in Publications 1 and 4 and item 5) below, but formation by sorting out monodisperse AgI grain or grain having a specific shape is not performed.
2) The blue light intrinsic absorption of AgI is based on the direct allowed transition between energy bands and therefore, the absorption coefficient of light at a wavelength of 400 to 430 μm is as large as about 100 times that of AgBr. This is advantageous in that the incident blue light is absorbed with good efficiency. However, since insufficiency arises later in the light-sensitive process and development process, a technique of forming an epitaxial AgX part (hereinafter simply referred to as an “epitaxial part”) with a low AgI content on the AgI grain and forming a chemical sensitization nucleus in the epitaxial part to form a latent image has been proposed. Publication 2 can be referred to for this technique and Publication 3 can be referred to for the blue light absorption coefficient.
3) Use of AgI grain for the photographic material is described in many publications and Publication 4 can be referred to therefor. However, AgI grains having a β type and a γ type are present in the vicinity of room temperature, many grain shapes are included, or large hunting occurs in the silver potential by the CDJ (controlled double jet) addition for the silver potential control because the silver potential of a reaction solution greatly changes due to slight dispersion of the I− concentration. Therefore, it is difficult to selectively form grains having only one grain shape and having a monodisperse size. No paper is known reporting an experiment succeeded in realizing this formation. By realizing the monodisperse formation, its use for light-sensitive materials is expected.
4) Publication 1 reports that when AgI grain is formed under the condition of excess Ag+ (Ag+ concentration>I− concentration), an AgI grain having a high face-centered cubic structure (hereinafter referred to as a “γ structure”) content is obtained, whereas when the grain is formed under the condition of excess I−, an AgI grain having a high hexagonal structure (hereinafter referred to as a “β structure”) content is obtained.
5) JP-A-59-119350 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) can be referred to for the AgI tabular grain emulsion having an aspect ratio of 8 or more and JP-A-59-119344 can be referred to for the AgI tabular grain emulsion having a γ type content of 90 mol % or more and an aspect ratio of 8 or more.
6) A yellow AgI emulsion grain (high in the content of α-type structure which is a body-centered cubic crystal) having an intrinsic absorption end in the vicinity of 480 nm is described in Publication 1 and U.S. Pat. No. 4,672,026.
7) U.S. Pat. No. 2,327,764 can be referred to for use of AgI fine grain as the UV absorbent in the UV filter layer of a color photographic material.
8) U.S. Pat. No. 4,520,098 can be referred to for the technique of allowing a high AgI content fine grain to be present near the AgX tabular grain (AgCl, AgBr, AgBrI or a mixed crystal of two or more thereof) spectrally sensitized at a high coverage and thereby reducing the amount of dye stains generated at the development processing.
9) Publication 5 describes a technique of mixing a high refractive index fine grain and/or one or more atom, molecule, ion or complex in the dispersion medium layer of a light-sensitive material to increase the refractive index of the dispersion medium layer and thereby reducing the light scattering intensity of AgX grain.
10) A symmetric tetradecahedral AgI grain where hexagonal faces parallel with each other have the same area is described in JP-B-63-30616 (the term “JP-B” as used herein means an “examined Japanese patent publication”) and U.S. Pat. No. 4,094,684.